1. Field of the Invention
The present invention relates to a transistor, and more particularly, to a vacuum channel transistor emitting thermal cathode electrons having a low driving voltage and stably emitting electrons and a method of manufacturing the vacuum channel transistor.
2. Description of the Related Art
In general, field emission devices apply an electric field to an electrode, that is, a cathode, in vacuum or under a specific gas atmosphere, and electrons are emitted from the cathode. The field emission devices are called cold cathodes and are used as an electron source of micro devices, sensors, and flat panel displays. In such field emission devices, the efficiency of emitting electrons varies according to the structure of the field emission devices, electrode materials, and the shape of the electrode.
Conventional field emission devices may be classified as a diode type formed of a cathode and an anode and a triode type formed of a cathode, a gate, and an anode. In the triode-type field emission devices, an electric field is applied to the gate adjacent to the cathode. Thus, the triode-type field emission devices may be driven in a lower voltage than that of the diode-type field emission devices. Also, current emitted to the anode and the gate of the triode-type field emission devices may be easily controlled and thus the triode-type field emission devices are being widely developed. Examples of the electrode materials of the field emission devices may include metal, silicon, and diamond. When silicon is selected as the electrode material, semiconductor processing equipment may be used and the field emission devices may be manufactured by being compatible with a semiconductor integrated circuit process.
However, due to a characteristic of the field emission devices in which electrons cut through the sharp surface of the cathode, electrical characteristics thereof are unstable, the uniformity of the electrical characteristics between the anode and the cathode is poor, and damage to the field emission devices due to excessive current may easily occur. For example, since the conventional field emission devices generally employ a sharp cathode tip structure, instability of emitting current, low efficiency, short life time, and low mass production may exist due to degradation of the tip in the cathode tip structure. In addition, the driving voltage for emitting electrons is very high in the conventional field emission devices.